A typical wireless communication system comprises a plurality of wireless communications devices exchanging data or voice data with each other. One example of a wireless communication system is a high frequency (HF) wireless communication system. The typical HF wireless communication system provides several benefits. For example, the HF wireless communication system offers potential worldwide communication capabilities with little to no infrastructure. Indeed, HF communication is popular with many amateur (HAM) radio operators, permitting one operator to readily contact another operator on another continent. The long range of HF wireless communication systems is to the result of the good propagation characteristics of HF waves through the Earth's atmosphere. Nevertheless, worldwide HF communication may only be available in the best of atmospheric conditions. The atmospheric conditions that may affect HF communications include, for example, sunlight/darkness at site of transmission and reception, season, solar sunspot cycle, solar activity, and polar aurora. Accordingly, the user may manually cycle through several frequencies to find a channel suitable for transmission.
A typical approach to this drawback in HF communication systems is automatic link establishment (ALE) methods. The ALE approach may typically include the transmitter device continuously scanning all available frequencies to determine corresponding quality-of-service (QoS) values for each frequency. Helpfully, the user of the HF communication system need not manually scan and evaluate the available frequencies. When a communication is initiated, the transmitter device selects the best available frequency for the desired transmission path.
Potential drawbacks to the ALE method may include lengthy link establishment times and limited bandwidth. For example, U.S. Pat. No. 5,930,685 to Straub discloses a method of ALE between two devices. This method inserts a 24-bit word in the call transmission for speeding up the link establishment. Moreover, even with ALE, the design of the typical HF wireless communication system may suffer from limited bandwidth, since existing ALE techniques lack capabilities to evaluate channels wider than 3 kHz, and to coordinate bandwidth selection between calling and called stations.
HF communication systems have typically utilized 3000 Hertz (3 kHz) of bandwidth. Several data signaling standards have been developed for these 3 kHz channels. Examples are US Military Standard 188-110B and NATO STANAG 4539. These standards support up to 9600 bits per second (bps) data communications over 3 kHz HF links. In addition, several ALE standards have been developed to support the 3 kHz bandwidth: US MIL-STD 188-141B and NATO STANAG 4538.
As the demand for higher data rates continues to grow, new waveforms/standards are being developed, which expand the utilized bandwidth from 3 kHz up to 24 kHz in 3 kHz increments and the data rate capability from 9600 bps to 76800 bps for HF skywave links and 120000 bps for HF surface wave links. These new HF waveforms are referred to as wideband HF waveforms. Developing and implementing new ALE systems to support these new standards may be very complex and costly to radio manufacturers, especially when multiple bandwidths are available for selection, i.e. 3 kHz, 6 kHz, 9 kHz, etc.